1. Field of the Invention
The present invention relates to apparatus for altering the position of a video image without rescanning of the originally generated image.
2. Description of the Prior Art
Prior art image repositioning systems, such as described in U.S. Pat. No. 3,420,953, by way of example, move or reposition a video image without rescanning of the originally generated image by altering the phase of the vertical and horizontal sync pulses fed to the camera or playback device which generates the original image or raster. While this approach has been satisfactory in some instances, it has been difficult to employ these techniques in many television systems, such as where the original image to be repositioned is from a video tape recorder, in which instance precise sync timing is required. In such prior art systems, due to the inertia in the mechanical components of the tape recorder, the recorder is not able to correct for timing errors caused by drift of horizontal and vertical timing in relation to each other, such as when an analog timing circuit is utilized to delay the sync feeding the video tape recorder and the vertical sync pulse is not generated in the proper relationship to the horizontal sync pulse. Thus, this inherent problem in video tape recorder head drums resulting from the mechanical inertia therein which prevents compensation for sync timing errors has produced unsatisfactory results in the prior art repositioning of such originally generated images. These disadvantages of the prior art are overcome by the present invention.